Techno-economic and environmental assessment of the landfill gas to energy potential of major Colombian cities

Abstract

Landfills account for significant methane emissions worldwide. However, municipal solid wastes can be energetically revalorized using landfill gas-to-energy (LFGtE) systems. This study assesses from a technical, economic, and environmental point of view the potential to implement LFGtE in major Colombian cities, including Bogota, Medellin, Cali, Barranquilla, Cartagena, and Bucaramanga, and the smaller capital city of Sincelejo. Municipal solid waste disposal rates in these cities are forecasted using the exponential smoothing (ETS) method. Additionally, methane emissions are forecasted using the first-order decay model, in line with the U.S. EPA methodology. Moreover, the methane generation capacity of the decomposable organic fractions of MSW is calculated following guidelines from IPCC. The assessment includes four scenarios with electricity and heat generation for each city. These scenarios consider using gas turbines, reciprocating internal combustion engines, and cogenerating electricity and heat. The economic performance is assessed with the net present value (NPV), the internal rate of return (IRR), the profitability index, the benefits-costs ratio, and the economic sensitivity analysis. Finally, the environmental performance is assessed by calculating the GHG emissions reduction potential and avoidance potential. The results show an electric power generation potential of 1.6 MWe to 47.5 MWe, a heat potential of 9.6 MW to 54.8 MW to produce steam, and 1.7 MW to 49.2 MW to produce hot water. The scenarios show economic profitability with NPV values of 5.3 million USD to 201.9 million USD.11M$: Millions of USD. At the same time, IRR varies from 14.9 % to 31.1%, a profitability index of 2.4 to 7.0 million USD, and a benefits-costs ratio of 1.3 to 1.6 million USD. Overall, scenarios consider using combustion engines to show the best economic performance. The potential to reduce greenhouse gas emissions was quantified in 1.2 MtCO2e to 40.0 MtCO2e, while the avoidance potential of greenhouse gas emissions varies between 0.1 and 4.3 MtCO2e depending on the scenario and the city.